NEU 301 Lecture Notes - Lecture 5: Gas Constant, Resting Potential, Nernst Equation
Document Summary
Calculates exact value of equilibrium potential for each ion in mv. Involves charge of ion, temperature, and ratio of external/internal ion conc. Eion = 2. 303 rt/zf log [ion]0 / [ion]i. [ion]i = icf conc using room temp 2. 303 x rt/f = 58 mv. Eion= 58/z long [ion]o / [ion]i z= charge (k=1, ca=2) *for every ten fold change in conc differences, there is a 58 mv change in equilibrium potential. Membrane potential influences ion flux direction and magnitude of ion flux depends on membrane potential. *electrical gradient will push ions in direction opposite of concentration. Potassium only ion thats higher inside; na/ca/cl higher outside. Switch to na permeable (pos membrane potential) and back again. -not exactly -58 mv due to slight permeability to other ions at rest. Need a technique to simultaneously control membrane potential and permeability changes. Allows hold of membrane potential even when permeability would normally change it. Also records current needed to keep cell at constant voltage.
